Adding SMS to Klaviyo is a five-minute toggle. Deciding which flows should actually use it takes more judgement than most merchants apply on day one. The common mistake is treating SMS as a bonus channel bolted onto every existing email flow, abandoned cart, welcome series, post-purchase, win-back, all of it, without asking whether a text genuinely improves that specific moment or just adds cost and irritates a subscriber who didn’t want another channel of noise.
SMS earns its place when a message is time-sensitive, high-intent, or something a customer actively wants to know the second it happens, a parcel arriving today, a restock of the one product they asked about, a cart about to expire. It doesn’t earn its place on a welcome email, a review request, or a monthly newsletter, where the same message works just as well, and costs a lot less, sitting in an inbox.
This post goes through Klaviyo’s core Shopify flows one by one, what the AU compliance basics look like for SMS specifically, why the cost-per-send difference actually matters to the decision, and what to check before you turn SMS on for an Australian number.
Why SMS Isn’t Just “Email But Faster”
Email and SMS behave differently, and the flow logic that works for one often doesn’t transfer cleanly to the other:
- Cost per send. SMS costs meaningfully more per message than email, Klaviyo bills SMS sends from a separate credit pool, priced per message, while email sending is bundled into the profile-based plan pricing. That difference alone should shape which flows get an SMS leg: a channel priced per send only makes sense where the send drives an outcome worth that cost.
- Attention and tolerance. A text lands with a notification on a locked screen. Subscribers tolerate a much lower volume of SMS before they opt out compared to email, where a slightly-too-frequent sender just gets ignored or filtered.
- Message length and format. SMS is not the place for a full product story, three images, and a footer of legal links, it’s a short, single-purpose nudge with one clear action.
- Consent is separate. In Klaviyo, SMS consent and email consent are tracked as distinct subscription statuses. A customer subscribed to your email flows is not automatically subscribed to SMS, and you need a genuine SMS opt-in before you can text them at all.
Given that, the flows worth building SMS into are the ones where speed and directness are the actual point, not every flow that happens to exist in your account already.
Flows That Genuinely Benefit From SMS
Abandoned Cart (High-Intent, Time-Sensitive)
Cart abandonment is one of the strongest cases for SMS, but only for the right segment, customers who added a reasonably high-value cart and have SMS consent. A short text 30-60 minutes after abandonment, alongside your existing email cart flow rather than replacing it, catches the window where someone is genuinely still deciding. Keep it to one SMS touch in the sequence rather than mirroring every email step; a cart flow that texts someone three times over two days will burn consent fast.
Shipping and Delivery Updates
This is arguably the single best use of SMS for a Shopify store. “Your order has shipped” and “your parcel is out for delivery today” are exactly the kind of information customers want the instant it happens, and they’re genuinely useful rather than promotional, which also tends to keep opt-out rates low, since customers see clear value in the message. These can be built as a dedicated Klaviyo flow triggered off Fulfilled Order or Order Shipped events synced from Shopify, running alongside your Shopify or carrier-native tracking notifications rather than duplicating them exactly.
Back-in-Stock Alerts
When a customer has specifically asked to be notified that a product is back, a text matches their intent far better than waiting for them to open an email days later, high-demand restocks can sell out again within hours. This only works if your back-in-stock app (or Klaviyo’s native back-in-stock flow, where available on your integration) supports collecting SMS consent at the point someone signs up for the alert, not just email.
Flash Sales and Time-Boxed Promotions
A genuinely short-window promotion, a 24-hour sale, a restock drop, a same-day-only code, is one of the few promotional use cases where SMS earns its cost, because the entire point is that the customer needs to act immediately. This should be occasional, not a standing weekly campaign, or it erodes the same urgency that makes it work.
Flows That Should Stay Email-Only
Welcome Series
A welcome flow is about introducing the brand, setting expectations, and building a relationship over several touches, none of that needs the urgency of a text, and hitting a brand-new subscriber with SMS immediately after they’ve only agreed to email can feel like a bait-and-switch if your sign-up form wasn’t explicit about SMS.
Post-Purchase and Review Request Flows
Asking for a review, sharing usage tips, or cross-selling a complementary product a week or two after delivery isn’t time-sensitive. Email format also suits this content better, you typically want images, a bit of context, and a clear but unhurried call to action, none of which fits a 160-character text well.
Browse Abandonment
Someone viewing a product page isn’t the same signal as someone adding to cart. Browse abandonment already has a much lower intent level, and texting people based on a page view is a fast way to burn SMS consent on a channel where the resulting conversion rate rarely justifies the cost or the annoyance.
Newsletters and Broadcast Campaigns
Regular content, new arrivals, general promotions, brand updates, belongs in email. It’s not urgent, it benefits from richer formatting, and sending it as SMS at any real frequency will generate opt-outs faster than almost anything else you do in Klaviyo.
Win-Back Flows (Usually)
Most lapsed-customer win-back sequences work fine in email. SMS can be worth testing as a single, later step in a win-back flow for genuinely high-value lapsed customers, but it’s not the default starting channel, a customer who’s gone quiet for months hasn’t demonstrated the kind of urgency that justifies a text.
Australian SMS Compliance Basics
This isn’t legal advice, and if you’re unsure about a specific situation you should check with a professional, but the general principles that apply to SMS marketing from an Australian business are worth building into your Klaviyo setup from day one:
- Consent has to be genuine and specific to SMS. Don’t assume that an email subscriber, or a Shopify checkout customer, has agreed to receive marketing texts, capture SMS consent explicitly, ideally through a dedicated checkbox or opt-in step, and keep a record of when and how it was given.
- Every message needs a clear way to opt out. Klaviyo handles STOP-keyword unsubscribes automatically once SMS is set up correctly, but it’s worth testing this yourself on your live number to confirm it works as expected.
- Don’t buy or import SMS lists. Consent has to come from the individual signing up with your store directly, imported contact lists without documented SMS consent are a compliance risk regardless of where they came from.
- Keep transactional and marketing messages distinct in tone and frequency. Shipping updates are generally viewed differently from promotional texts, but that doesn’t remove the need for a consent basis to send them, check how your Shopify and Klaviyo consent settings are configured so transactional-style flows aren’t relying on marketing opt-in alone, or vice versa.
Treat AU spam and consent obligations as a general framework to build good habits around, not a box to tick once, review your consent capture points (checkout, pop-ups, SMS sign-up forms) periodically as your store and its apps change.
Klaviyo SMS Setup Notes for Australian Numbers
A few things worth checking before you launch SMS flows on an AU-based Shopify store:
- Confirm your sending number type. Klaviyo provisions SMS sending numbers by region and use case, the setup available for an Australian business account may differ from a US-based one, so check current number options inside your Klaviyo SMS settings rather than assuming what applies elsewhere.
- Enable SMS consent collection at checkout. Shopify has a native checkout field for SMS marketing consent, which can sync through to Klaviyo, turn this on rather than relying solely on a separate pop-up.
- Set up your STOP/START keyword handling and test it with a real message before sending to your full list.
- Segment by SMS consent, not just email consent, when building any new flow, Klaviyo will only send SMS steps to profiles with active SMS subscription status, but it’s worth double-checking flow filters explicitly rather than assuming.
- Watch your SMS credit usage in the first few weeks after launch, since cost per send adds up quickly if a flow with a large audience gets an SMS step added without checking volume first.
A Simple Decision Checklist for Any Flow
Before adding an SMS step to a Klaviyo flow, run it through these questions:
- Is this information genuinely time-sensitive (needs to be seen within hours, not days)?
- Does the customer’s action show high purchase intent (cart add, stock alert sign-up) rather than passive browsing?
- Can the message be said clearly in one or two short sentences?
- Do we have explicit, documented SMS consent for this audience segment?
- Is the expected lift in conversion or satisfaction worth the higher per-send cost compared to email?
If a flow doesn’t clear most of these, it’s a reasonable candidate to stay email-only, at least until you’ve tested otherwise.
When to Bring in a Specialist
Getting SMS flows technically live in Klaviyo is straightforward. Getting the decisions right, which flows actually justify the cost, how consent is captured across your Shopify checkout and pop-ups without creating gaps, and how to structure send frequency so SMS doesn’t cannibalise your email engagement, takes more judgement, especially for stores running SMS for the first time. If you’re not confident your current SMS setup (or lack of one) is doing more good than harm, that’s a natural fit for Nexly’s Klaviyo and email marketing service, where we look at consent capture, flow structure, and channel mix together rather than treating SMS as an isolated add-on.
FAQ
Does adding SMS to Klaviyo cost extra on top of my existing plan?
Yes, Klaviyo prices SMS sending separately from email, generally through a credit-based system billed per message sent, on top of your core Klaviyo plan. Exact current pricing is worth checking directly in your Klaviyo account, since it varies by region and message volume.
Can I use the same consent list for email and SMS in Klaviyo?
No. Klaviyo tracks email and SMS subscription status separately for each profile, and a customer needs to opt in specifically to SMS marketing before you can legally and technically send them marketing texts, even if they’re already subscribed to email.
How many SMS touches should an abandoned cart flow include?
Generally one, positioned alongside your existing email cart-recovery steps rather than replacing them. Multiple SMS touches in a single cart flow tend to push opt-out rates up quickly without a proportional lift in recovered carts.
Should shipping notifications come from Shopify or from Klaviyo?
Either can work, Shopify has its own native order and shipping notifications, and Klaviyo can also send shipping-update SMS built off Shopify fulfilment events. The main thing is not duplicating the same message from both systems at once, which reads as spammy even when the content is genuinely useful information.
Is SMS worth it for a small or newly launched Shopify store?
It can be, but usually for a narrower set of flows than a larger store would run, shipping updates and a single cart-recovery touch are often the highest-value starting point, since a smaller send volume keeps costs low while you build up genuine SMS consent over time, rather than launching a full SMS programme across every flow on day one.
If you’re weighing up whether SMS is worth adding to your Klaviyo account, or your existing flows need a proper audit, book a call with Nexly and we’ll go through what’s actually worth automating for your store.
